Apparatus for and method of refining finely divided material



Oct. 16, 1934. A. L. WHITESIDE APPARATUS FOR AND METHOD OF REFININGFINELY DIVIDED MATERIAL Filed Jan. BET 1931 2 Sheets-Sheet l R n M 4ATTORNEY A. WHITESIDE APPARATUS FOR AND METHOD OF REFINING FINELYDIVIDED MATERIAL 2 Sheets-Sheet 2 Fil ed Jan. 22, 1931 Patented Oct. 16,1934 UNITED STATES APPARATUS FOR AND METHOD OF REFIN- ING FINELY DIVIDEDMATERIAL Arthur L. Whiteside, East Orange, N. J., assignor to PulvisAktiengesellschaft, Glarus, Switzerland, a corporation of SwitzerlandApplication January 22, 1931, Serial No. 510,409

9 Claims.

My invention relates to the refining of finely divided material and hasparticular reference to the refining of finely divided metallic materialsuch as commercial chilled shot or the like.

6 For certain uses it is desirablelto provide a mass of finely dividedmetallic material having the general characteristics of a-dry powder andconsisting entirely of individual substantially perfectly sphericalbodies of substantially uniform size, so that such material may besubjected in use to impact and to relative movement of the individualbodies with respect to each other without causing breakage of theindividual bodies or undue wear thereof because of the presence ofabrading, non-spherical particles.

Metallic material having the above characteristics is particularlyuseful as a power transmitting medium in clutches of the general typedisclosed in my copending application Serial No. 508,818, filed January15, 1931, Patent No. 1,910,- 270, issued May 23, 1933, and for purposesof illustration in the present application I will describe my invention,which includes both a novel method and novel apparatus, in connectionwith the refining of commercial chilled shot for use in such clutches,although it is to be understood that neither the method nor theapparatus herein disclosed are limited to the refining of thisparticular material.

For an understanding of the objects and nature of the inventionreference may best be had to the ensuing detailed description, taken inconjunction with the accompanying drawings forming part of thisspecification and illustrating the novel apparatus provided foreffecting one of the steps in the method.

In the drawings, Fig. 1 is a plan view of a device constructed inaccordance with the invention and adapted to effect a separatingoperation on 40 finely divided material;

Fig. 2 is a front elevation of Fig. 1; and

Fig. 3 is a side elevation looking from the left of Fig. 1 andillustrating the device in horizontally inclined position.

In order to produce suitable material for use as a power transmittingmedium in clutches of the type above referred to, it is desirable thatthe material have the following characteristics: (a) it should containonly substantially spherical bodies; (b) the individual bodies should beof substantially uniform size; the individual bodies should each bestructurally sound to minimize the possibility of fracture thereof intonon-spherical particles when the material is in use; and (d) 5 thesurfaces of the individual bodies should be coated with suflicientlubricant of relatively dry nature, such for example as graphite, toprevent abrasive metal to metal contact between the individual bodies,but the quantity of graphite or like substance employed should not besufiicient 3 r to destroy the characteristic of dryness of the material.

In order to refine finely divided material, such for example ascommercial chilled shot, into a material having the characteristicsabove set forth, I propose, in accordance with my invention, to removefrom the commercial shot all oversize shot and oversize foreignparticles by passing the shot through a screen having interstices ofknown area, which screening operation serves to establish the upperlimit of size of the bodies in the material used.

The material which is not rejected in the screening operation issubjected to impact in order to crack or break any defective bodies inthe material. subjection of the material to im 'pact may be carried outin various known Ways.

For example, the material may be tumbled in a tumbling barrel which,depending upon its construction, may or may not have steel bars or otherlike impact members placed in the barrel with the material. When impactmembers are not employed the tumbling, barrel should be of known formequipped with internal bafiles or plates adapted to lift the materialupon rotation of the barrel in order to secure impact due to dropping ofthe material within the barrel.

Another suitable means for subjecting the material to impact is theordinary known form of pneumatic sand blasting equipment into which thematerial to be subjected to impact is introduced instead of sand, thedesired impact being secured by the striking of the material against thesurface toward which the blast is directed. In this connection, it is tobe noted that commercial chilled shot of small diameter is frequentlyused in lieu of sand in certain commercial sand blasting operations, andin plants where the cleaning of castings or other objects by thisprocess is required, desirable economies may be effected by making thisstep of the present process perform an additional useful function.

The material which has been subjected to impact treatment is passedthrough a screen hav-' ing interstices of smaller area than the firstscreen employed, and all bodies, fragments and foreign particles of asize smaller than a predetermined minimum are separated from the usefulmaterial by this screening operation. The retained material consists ofbodies which are of uniform size between the limits established by thescreening operations and which. are structurally sound. I

I prefer to carry out the above described steps in the order named, thatis, first screening the material to remove oversize material, thensubjecting the screened material to impact treatment, and then screeningthe impact treated ma terial to remove undersize bodies, but this orderto steps is not essential. By following the order of steps specified,the quantity of material which must be handled in the step of impacttreatment is reduced, and the screening for the removal of undersizebodies, when it is preceded by the impact treatment, permits the removalat one time not only of all of the undersize bodies in the originalcommercial material, but also of the undersize fragments produced by thebreakage incident to the impact treatment. The material which has beenscreened to substantially uniform size and from which structurallydefective bodies have been removed is next subjected to a treatmentwhich separates the substantially perfectly spherical balls from allballs which are of other than spherical shape and from all fragments andforeign particles which may not have been removed from the material inthe screening operationsl' I havefound that the substantially perfectballs in the material may be readily separated from all imperfectmaterial if the material to be separated is dropped on a horizontallyinclined moving surface, since the perfect balls will 'take paths oftravel, after striking the surface, which are considerably differentfrom the paths of travel taken by the imperfect bodies comprising theremainder of the material. The surface upon which the material isdropped is preferably of glass, and it is preferable to drop thematerial on such surface in a zone where the surface inclines upwardlywith respect to the direction of movement of the surface. When thematerial is dropped on such a surface the perfect balls will roll downthe inclined surface and in substantially straight lines, so that allsuch balls will reach the edge of the surface in a well defined zonewhich is fixed with respect to the position of the zone in which thematerial is dropped on the moving surface. The imperfect bodiescomprising the remainder of the material'will either roll relativelyslowly and in irregular paths of travel which, due to the movement ofthe surface, prevent them from reaching the edge of the surface in thezone reached by the perfect balls, or, if they have flat fac'es, willremain on the surface and be carried away from the zone of movement ofthe perfect balls by the moving surface. Bodies having flat faces andtending to remain on the surface may readily be removed therefrom atstill another zone by brushing or other mechanically equivalent means.

The more specific details of this step in the method will appear morefully in connection with the description of the preferred form ofapparatus for carrying this step into effect which will 'allel framebars 12 and 13, joined together by means of end cross members 14 and 15and a cenduce a refined material in which the individual balls arebetween 20 and 23 thousandths of an inch in diameter, these limits beingestablished by pre-' vious screening operations.

The device comprises a frame indicated generally at 10, said frame beingadapted to be mounted in adjustably tilted position upon a suitable baseor support 11., Frame 10 comprises two partral cross member 16, whichhas an overhung portion 16'. Vertical supports 17 and 18 serv to holdthe frame member 19 above member 12. The entire frame is pivotallysupported by means of suitable axially extending pins 20 and 21 passingthrough the vertical webs of angle plates 22 and 23 secured to the base11, and the angle of inclination of the frame is determined by means ofadjusting bolts 24 and 25 passing through the member 13 and providedwith lock nuts 26 and 27. The frame is preferably provided with anindicator to show the angle of inclination, this indicator convenientlycomprising a pivotally hung pointer 28 adapted to cooperate with anarcuate, scale 29 secured to the vertical support 1'7. 5,110

A vertical shaft 30 is rotatably mounted cen trally of the frame,preferably in anti-friction bearings, between the vertically spacedmembers 12 and 19. The portion of this shaft between the verticallyspaced members is shouldered as at 31, this shoulder serving to supporta circular member in the form of a plate 32, the upper surface of whichis preferably of glass. Plate 32 may conveniently consist entirely ofglass. The plate 32 is secured against relative rotation with respect toshaft 30 by means of a clamp nut 33 screwed on the shaft 30, above theplate. Below the plate 32, shaft 30 has secured thereto a bevel drivegear 34 meshing with a pinion 35, the latter being secured to a shaft 36mounted in suitable bearing brackets 37 and 38 on the frame. Shaft 36 isdriven through the medium of a drive chain 39 which receivs its powerfrom the speed reducing gear 40 mounted on member 13, said gear beingdriven by a motor 41 also mounted onthis frame member.

The power delivering shaft on the speed reducing gear 40 drives a secondshaft 42 located above plate 32 and provided with an eccentric 43adapted to oscillate a material feeding member 44 mount- I ed inbrackets 45 attached to the frame member 19. A hopper 46 is mounted onthe frame above the feeding member 44 and comprises a spout 47 extendingdownwardly to a point close to the bottom of member 44. A number ofholes 48' are provided in the bottom of member 44, these holes beingspaced from each other and preferably extending in a line generallytransverse to the direction of movement of the plate immediately be lowthe feeding member. In the feeding member illustrated four holes areemployed, but this number may be varied, althoughthe number should berelatively small for reasons which will hereinafter appear.

Shaft 42 is extended as at 42', the outer end of the shaft beingsupported in a bearing 49 carby the dotted arrows at toward the box 53.Their ried by a block 50 secured, to the outer end of the frameextension 16. The extended portion 42 of shaft 42 has mounted thereon abrush 51 adapted to sweep the plate 32 and the portion of the plateabove the brush is preferably enclosed by a cover 52 which may beremovably secured to the frame in any suitable manner.

The good material separated by the device is conveniently collected bymeans of a box 53, into which it is directed by the deflecting strip orguard 54, while the pan 55 and box 56 serve to collect the imperfectmaterial separated by the device.

In a device suitable for separating material of the dimensions abovespecified I have found that a suitable diameter for plate 32 is about 30inches and that the plate should be rotated at a speed of about tenrevolutions per minute. The shaft 42 for rotating brush 51. and foroscillating feeding member 44 should operate at about 180 revolutionsper minute and by using a speed reducing gearing having a ratio of tento one the device may be operated by a small high speed electric motorof one-eighth horse power. The speeds at which the brush and the feedingmember operate need not be the same, and they may vary considerablywithout materially affecting the operation of the device. The speed atwhich the plate rotates, however, is a more important factor andvariation in this speed will affect the manner of operation of thedevice.

For separating material of the character described I have found thatholes 50 thousandths of an inch in diameter are suitable for use in thefeeding member and that the device should be tilted approximately 10with respect to the horizontal to secure the best results. Obviously, ifmaterial comprising bodies of a materially different size is to beseparated-the size of the holes in the feeding member should be changed,and also, depending upon the size and character of the material, theangle of inclination of the plate may require change in order to securethe best results.

In operation,- material is fed from the hopper 46 to the feeding member44 and the oscillating movement of this member causes the material to bedropped in a scattered state through the holes 48 to the surface ofplate 32. The projection of hopper 46 to a point adjacent to the bottomof the feeding member 44 serves two useful functions. It maintains thematerial in the feeding member at a substantially constant depth and therelative motion between the lower end of the hopper and the material inthe feeding member serves to agitate the material and facilitates aneven rate of feed through the several holes 48.

It is to be noted that the scattering of the material is important tothe successful operation of the device, since if the separating actionis to be effective, individual bodies in the material should fall to thesurface of the plate free and clear of contact with, or interferencefrom, other bodies. Obviously, this scattering action in the feedingmechanism can be obtained by other than oscillating movement of thefeeding memher, but I have found this motion to be both easy to obtainand effective in use. In the device described, the member 44 has a pathof travel of about one inch.

Upon striking the surface of the plate the individual bodies bounce orroll from their respective points of contact and, due to the inclinationof the surface of the plate, the perfectly spherical bodies rolldownwardly along the inclined surface in the general direction indicatedpaths of travel are affected to some extent by the movement of theplate, which is rotating in the direction indicated by the arrow b, butdue to the slow speed of rotation of the plate and the short paths ofrelatively rapid roll of the perfectly spherical bodies, they leave theplate in a definite zone comprising a relatively restricted portion ofthe circumference of the plate having a fixed position with respect tothe location of the feeding zone.

The imperfect bodies which are capable of rolling take irregular pathsof travel and roll at a slower speed than the spherical bodies.Consequently such imperfect bodies are carried upwardly by the movingplate and take various irregular paths of travel such as that indicatedby the dotted arrow c, to be finally removed from the plate by theaction of the brush 51. Some of these-imperfect bodies may leave thesurface of the plate in the upper portion to drop into the pan 54, butthe amount of material leaving the part of the plate under which thispan is placed is relatively small. Imperfect bodies having fiat facescome to a position of rest on the plate and are carried around therebyto the brush 51, which serves to remove these bodies and also theirregularly rolling bodies which follow paths of travel similar to thatindicated at c.

Many changes and variations in the apparatus and method hereinbeforedescribed by way of example may be made within the scope of theinvention, which also contemplates the use of some of the steps of themethod to the exclusion of others. It is further to be understood thatthe invention is applicable to the refining of. various finely dividedmaterials of different nature and intended for uses other than in powertransmitting mechanism.

What I claim is:

1. The method of refining commercial shot which comprises subjecting theshot to impact to crack defective shot and dropping the shot inscattered state on a horizontally inclined moving surface to separatesubstantially perfect shot from the remaining shot due to the differentpaths of travel of the shot after striking said surface.

2. The method of refining commercial shot which comprises tumbling theshot to crack defective shot and dropping the tumbled shot in scatteredstate on a horizontally inclined moving surface to separatesubstantially perfect shot from the remaining shot due to the differentpaths of travel of the shot after striking said surface.

3. The method of preparing commercial shot for use as a powertransmitting medium in clutches or the like which consists in subjectingthe shot to impact to crack defective shot, dropping the shot inscattered state on a horizontally inclined moving surface to separatesubstantially perfect shot from the remaining shot due to the differentpaths of travel of the shot after striking said surface, and coating thesubstantially perfect shot with graphite.

4. The method of preparing commercial shot for use as a powertransmitting medium in clutches or the like which consists in subjectingthe shot to impact to crack defective shot, dropping the shot inscattered state on a horizontally inclined moving surface to separatesubstantially perfect shot from the remaining shot due to the differentpaths of travel of the shot after striking said surface, tumbling theseparated sub- 5g stantially perfect shot in the presence of graphiteand screening the graphite treated shot to remove excess graphitetherefrom.

5. The method of preparing commercial shot for use as a powertransmitting medium in clutches or-the like which consists in screeningthe commercial shot to establish a maximum size of shot, tumbling thescreened shot to crack defective shot, screening the tumbled shot toestablish a minimum size of shot, dropping the sized shot in scatteredstate on a horizontally inclined moving surface to separate thesubstantially perfect shot from the remaining shot due to the differentpaths of travel of the shot after striking said surface, and coating theseparated substantially perfect shot with graphite.

6. The method of preparing commercial shot for use as a powertransmitting medium in clutches or the like which consists in screeningthe commercial shot to establish a maximum size of shot, tumbling thescreened shot in the presence of impact members to crack defective shot,screening the tumbled shot to establish a minimum size of shot, droppingthe sized shot in scattered state on a horizontally inclined movingsurface to separate the substantially perfect shot from the remainingshot due to the different paths of travel of the shot after strikingsaid surface, tumbling the separated perfect shot in the presence ofgraphite and screening the graphite treated shot to remove excessgraphite therefrom.

7. A device for refining finely divided metallic material containingsubstantially spherical bodies comprising a frame, means for tilting theframe, a glass plate rotatably mounted on the frame and adapted to tilttherewith, feeding means for dropping said material on said plateincluding a stationary hopper, a movable feeding 'member mounted on theframe beneath the hopper, the lower end of said hopper extending toadjacent the surface of said feeding member, and means mounted on theframe for rotating the plate and for oscillating said feeding memberwhereby the adjacent stationary end of said hopper agitates material insaid feeding member.

8. A device for refining finely divided metallic material containingsubstantially spherical bodies comprising a frame, means for tilting theframe, a glass plate rotatably mounted on the frame and adapted to tilttherewith, feeding means for dropping said material on said plateincluding a movable feeding member mounted on the frame and a revolvablebrush mounted on the frame generally radially of and contacting saidplate, and means mounted on the frame for rotating the plate and thebrush and for oscillating the feeding member.

9. A device for refining finely divided metallic material containingsubstantially spherical bodies comprising a frame, means for tilting theframe, a glass plate rotatably mounted on the frame and adapted to tilttherewith, feeding means for dropping said material on said plateincluding a. movable feeding member mounted on the frame, a motormounted on the frame, means including speed reducing gearing actuated bysaid motor for rotating said plate at relatively low speed, and meansactuated by said motor for oscillating said feeding member and forrotating said brush at speeds materially greater than the speed ofrotation of said plate.

ARTHUR L. WHITESIDE.

